(1) Field of the Invention
The present invention pertains to a microsurgical laser probe used primarily in ophthalmic surgery. The probe has a handle and a tubular sleeve and a distal end portion of an optic fiber projecting from the sleeve can be caused to bend relative to the sleeve by manual manipulation of a mechanism on the probe handle.
(2) Description of the Prior Art
In ophthalmic surgery, various different types of instruments are available for use by the surgeon to transmit laser energy to a surgical site in the interior of the eye. The typical microsurgical laser probe comprises a handle with a small cylindrical metal sleeve projecting from a distal end of the handle. An optic fiber, having a proximal end with a connector for coupling to a source of laser light, passes through the center of the handle and the sleeve of the probe. The distal end of the optic fiber is positioned adjacent the distal end of the sleeve. In instruments of this type, the sleeve can project straight from the handle of the instrument or can have a slight bend or curve as it projects from the instrument handle.
Efficient delivery of laser light in the eye interior toward the anterior or front portion of the retina is often awkward to the surgeon using a straight laser probe. This is due to the positioning of the incision or instrument entry site in the eye relative to the target area or surgical site of the laser light being transmitted. This is illustrated in FIG. 1 where an area A of the eye interior is inaccessible to the straight tip of the laser probe shown. The use of curved laser probes such as that shown in FIG. 2 allows for a greater range of coverage inside the eye, thereby minimizing the risk of hitting the lens of the eye with the laser light and overcoming the disadvantages of the straight sleeve laser probe discussed above. However, curved laser probes cannot be inserted through straight cannulas and therefore must be directed through the eye incision site itself.
The optimal deliver of laser light to a surgical site in the eye requires that the laser be directed perpendicular to the target area of the surgical site. Directing a straight laser probe at anterior or forward portions of the retina causes the approach angle, or angle of incidence of the laser light, to be large. In this situation the optimal delivery of laser light to the surgical site cannot be achieved. Additionally, torquing or manipulating the tubular sleeve of the straight probe in the entry incision to reduce the angle of approach of the laser light to the surgical site in these awkward areas often produces excessive, and sometimes harmful stresses around the incision of the eye. Often the only way for the surgeon to overcome this situation is to create a second incision site for insertion of the laser probe. These problems can be overcome by using a curved laser probe that can effectively eliminate the use of a secondary incision site since an increased area in the eye interior is accessible from the single entry site as illustrated in FIG. 2. Currently available curved laser probes are able to access more anterior or forward areas of the eye interior than can be achieved with straight laser probes. However, because their curvatures are fixed, curved laser probes are not efficient at directing laser energy to areas even more anterior or more forward in the eye that would require a tighter bend or curvature of the probe sleeve, or areas at the far end or posterior of the retina which would require a straight sleeve laser probe due to the approach angle.
To overcome these disadvantages of prior art straight and curved laser probes, what is needed is an adjustable directional laser probe that is capable of reducing the approach angle or angle of incidence of light toward the surgical site, thereby providing ease of access and reduced instrument manipulation at the target site, reduced tissue stress at the point of entry, and improved laser focusing by directing the laser energy more perpendicular to the target surgical site.